1. Field of the Invention
This invention relates generally to hydrogeology and more particularly, but not by way of limitation, to water, sediment and erosion control apparatus and methods.
2. Description of the Prior Art
Construction often disturbs trees, grasses, bushes and other elements which naturally control run-off water, sediment and erosion. Typically, the bare earth is exposed in a construction site which, if no controls are implemented, significant erosion and other water damage can occur. In fact, the United States Environmental Protection Agency has issued regulations requiring contractors whose construction operations disturb five or more acres of land to implement erosion and sediment controls. See Federal Register, vol. 57, no. 175, p. 41,217, Sep. 9, 1992.
One type of sediment and erosion control device which is often used is hay or straw bales. However, hay bales are seldom satisfactory. First, they are difficult to install. The weight and associated factors of hay bales make installation a labor intense task. Second, long wooden or steel stakes must be used to hold the bales in place. These are expensive and difficult to install and remove. Third, quality control for hay or straw bales is very seldom available, resulting in a poor quality material often being used. Fourth, hay bales placed in a barrier position cannot be joined together to stop water penetration, resulting in erosion between and underneath the bales and eventually failure of the barrier. If water does not flow under or penetrate between the bales, it will often flow over the top causing erosion of the soil directly behind and beneath the bales and eventually resulting in failure. Additionally, hay or straw bales become soil laden very quickly and cannot be reused. The wire or string holding the hay together often deteriorates and breaks. Finally, hay bales are not readily available in some areas and, due to their weight and bulkiness, cannot be shipped to these areas in a cost-efficient manner.
Another type of erosion and sediment control device is a silt fence. A silt fence is a permeable barrier made of filter fabric buried at the bottom, stretched and supported by posts. However, silt fences generally do not have the structural strength to collect soil and sediment. Furthermore, because silt fences are not designed to withstand high heads, the general use of silt fences is limited. Furthermore, silt fences require a great amount of maintenance.
Many other devices and methods have been and are currently being used: check dams, detention basins, temporary and permanent earth diversions, rock or cement-lined waterways and outlets, mulching, surface roughening and temporary seeding. See Storm Water Management For Construction Activities--Developing Pollution Prevention Plans And Best Management Practices, United States Environmental Protection Agency, chapter 3, September 1992. These devices and methods suffer similar problems including a lack of effectiveness, intensive labor requirements and expense.
Another application where it is necessary to control water involves flood situations. Sand-filled bags are often used to build a barrier wall, for example, surrounding a house or lining a river bank. However, sand bags are heavy and do not have great lateral strength to support a high wall of water. Furthermore, due to short warning times and the labor intensive nature of preparing a sand bag barrier, often there is simply not enough time to build a sand bag barrier prior to flooding.
Thus, there is a need for improved water, sediment and erosion control apparatus and methods which are effective, easily and quickly installed and removed, lightweight, inexpensive, durable and reusable.